Artificial spinal disk prosthesis

ABSTRACT

Intervertebral endoprosthesis discs suitable for surgical implantation between two vertebrae having and methods thereof. The prosthetic disc may have an endoprosthesis body including an anterior region and a posterior region designed to be positioned between a first vertebra and a second vertebra with a first and second movable insert positioned rotatably in anterior cavities and is rotatable to adjust the fasteners.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/046,000, filed Jul. 26, 2018 (published as U.S. Pat. Pub. No.2018-0344472), which is a continuation of U.S. patent application Ser.No. 15/367,456, filed Dec. 2, 2016, now U.S. Pat. No. 10,034,763, whichis a continuation of U.S. patent application Ser. No. 14/927,627, filedOct. 30, 2015, now U.S. Pat. No. 9,539,105, which is a continuation ofU.S. patent application Ser. No. 14/474,528, filed Sep. 2, 2014, nowU.S. Pat. No. 9,198,775, which is a continuation of U.S. patentapplication Ser. No. 13/352,534, filed Jan. 18, 2012, now U.S. Pat. No.8,852,281, which claims priority to provisional Application No.61/433,791, filed Jan. 18, 2011 (expired). These applications areincorporated herein by reference in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates in general to the field of artificialprosthesis, and more particularly, to an improved artificial prosthesisfor use in spinal joints with reduced material fatigue and improvedpatient comfort.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with spinal joint prosthesis. A variety of artificialprosthesis are used to replace chronically injured or rupturedintervertebral discs and range from plate inserts, ball and socketjoints, gel filled enclosures, spring-biased plates, plate and jointcombinations and others.

For example, U.S. Pat. No. 6,846,328, issued to Cauthen teaches anotherarticulating spinal implant. The articulating intervertebral discreplacement implant is formed from two elements, each engaging one of anadjacent pair of vertebra and capable of an articulating motion thatresists compression and lateral movement between the vertebra, butallows the adjacent vertebra to articulate about an instantaneous axisof rotation.

Another example is taught in U.S. Pat. No. 6,039,763, disclosesarticulating spinal disc prosthesis that is designed to articulate in amanner resembling a human knee articulation. Briefly, the artificialspinal disc includes two plates each having a planar outer surface andan articulating inner surface. The planar outer surfaces contact and areaffixed to adjacent inferior and superior surfaces of two adjacentvertebrae. The interior articulating surfaces of the artificial spinaldisc are shaped generally to have one or more complementaryconvex/concave shaped articulating portions that are shaped andarticulate in a manner similar to a human knee.

Another example of intervertebral disc prosthesis is taught in U.S. Pat.No. 5,401,269, which discloses an intervertebral disc endoprosthesisthat includes two prosthesis plates that have a prosthesis core thatcooperates with at least one prosthesis plate via an articulatingsurface permitting a rotational movement. The two plates are connectedto the end plates of adjacent vertebrae. To control rotational movementaround the vertical axis, the articulating surface forms curved archesof different average radius in the median section and in the frontalsection. The radius of curvature in the sagittal section is less than inthe frontal section.

SUMMARY OF THE INVENTION

The present invention provides an intervertebral endoprosthesis disc forsurgical implantation between two vertebrae having an endoprosthesisbody comprising an anterior region and a posterior region designed to bepositioned between a first vertebra and a second vertebra; at least afirst anterior cavity and a second anterior cavity positioned in theanterior region; a first movable insert having a first fastener apertureand positioned rotatably in the first anterior cavity, wherein the firstmovable insert is rotatable in the first anterior cavity; and a secondmovable insert having a second fastener aperture and positionedrotatably in the second anterior cavity, wherein the second movableinsert is rotatable in the second anterior cavity independent of thefirst movable insert; and wherein a first insertion angle of a firstfastener extending through the first fastener aperture may be adjustedby rotating the first movable insert and a second insertion angle of asecond fastener extending through the second fastener aperture may beadjusted by rotating the second movable insert.

The present invention also provides a surgical cage for surgicalimplantation between two vertebrae of a spinal column, said surgicalcage having a body that may be secured to a vertebra with a surgicalscrew; a first structure within the body for increasing an angle atwhich a first surgical screw may be screwed into a vertebra that isadjacent to a top the body; and a second structure within the body forincreasing an angle at which a second surgical screw may be screwed intoa vertebra that is adjacent to a bottom the body. The first structurecomprises portions that define an aperture through the first structurefor receiving the first surgical screw; the second structure comprisesportions that define an aperture through the second structure forreceiving the second surgical screw; a portion of the body that definesapertures through the body for receiving the first structure and thesecond structure; wherein the first structure is rotatably mounted withrespect to the body to allow the aperture though the first structure tobe rotated to increase an angle at which the first surgical screw may bescrewed into the vertebra that is adjacent to the top of the body, andwherein the second structure is rotatably mounted with respect to thebody to allow the aperture though the second structure to be rotated toincrease an angle at which the second surgical screw may be screwed intothe vertebra that is adjacent to the bottom of the body.

The first structure having portions that define an aperture through thefirst structure for receiving the first surgical screw comprises aportion of first cylindrically shaped shell that is rotatably mounted onthe body; and the second structure having portions that define anaperture through the second structure for receiving the second surgicalscrew comprises a portion of second cylindrically shaped shell that isrotatably mounted on the body.

An vertebral prosthesis for surgical implantation across at least twovertebrae having a first attachment fixture and a second attachmentfixture each attachment fixture comprising an anterior region and aposterior region designed to be positioned on the surface of a firstvertebra, at least a first anterior cavity and a second anterior cavitypositioned in the anterior region, a first movable insert having a firstfastener aperture and positioned rotatably in the first anterior cavity,wherein the first movable insert is rotatable in the first anteriorcavity, and a second movable insert having a second fastener apertureand positioned rotatably in the second anterior cavity, wherein thesecond movable insert is rotatable in the second anterior cavityindependent of the first movable insert, wherein a first insertion angleof a first fastener extending through the first fastener aperture may beadjusted by rotating the first movable insert and a second insertionangle of a second fastener extending through the second fasteneraperture may be adjusted by rotating the second movable insert; and anstabilization body attached to the first and the second attachmentfixtures to extend from the first vertebra to the second vertebra.

The present invention also provides a method of stabilizing a two ormore vertebra by positioning an intervertebral endoprosthesis betweentwo vertebrae, wherein the intervertebral endoprosthesis comprises: anendoprosthesis body comprising an anterior region and a posterior regiondesigned to be positioned between a first vertebra and a secondvertebra, at least a first anterior cavity and a second anterior cavitypositioned in the anterior region, a first movable insert having a firstfastener aperture and positioned rotatably in the first anterior cavity,wherein the first movable insert is rotatable in the first anteriorcavity, and a second movable insert having a second fastener apertureand positioned rotatably in the second anterior cavity, wherein thesecond movable insert is rotatable in the second anterior cavityindependent of the first movable insert; inserting a first fastenerthrough the first fastener aperture; adjusting a first insertion angleof a first fastener extending through the first fastener aperture byrotating the first movable insert; inserting the first fastener into thefirst vertebra; securing a second fastener through the second fasteneraperture; adjusting a second insertion angle of the second fastenerextending through the second fastener aperture by rotating the secondmovable insert; and securing a second fastener through the secondfastener aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures and in which:

FIGS. 1A and 1B are side views of the intervertebral disc endoprosthesisin operation.

FIG. 2 is an image of the intervertebral disc endoprosthesis of thepresent invention.

FIG. 3 is a top view of the intervertebral disc endoprosthesis of thepresent invention.

FIG. 4 is an image of the intervertebral disc endoprosthesis inoperation of the present invention in operation.

FIG. 5 is another image of the intervertebral disc endoprosthesis of thepresent invention.

FIG. 6 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention.

FIG. 7 is an image of another embodiment of the intervertebral discendoprosthesis of the present invention.

FIG. 8 is an image of another embodiment of the intervertebral discendoprosthesis of the present invention.

FIG. 9 is an image of another embodiment of the intervertebral discendoprosthesis of the present invention.

FIG. 10 is an image of another embodiment of the intervertebral discendoprosthesis of the present invention.

FIG. 11 is an image of another embodiment of the intervertebral discendoprosthesis of the present invention.

FIG. 12 is an image of another embodiment of the intervertebral discendoprosthesis of the present invention.

FIG. 13 is an image of the vertebral prosthesis of the presentinvention.

FIG. 14 is a side view of the vertebral prosthesis of the presentinvention in operation.

FIG. 15 is an image of a screw used in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

The spine encloses the spinal cord and includes thirty-three vertebrae.The vertebrae are divided into four regions that include the uppermostseven vertebrae referred to as the cervical vertebrae, followedsequentially by the twelve thoracic vertebrae, the five lumbar vertebraeand the five sacral vertebrae. The final four vertebrae are referred toas the coccygeal vertebrae.

Although the vertebrae of each region have a different structure, thebasic vertebra structure has certain similarities. The vertebral body isthe anterior part of the vertebra and is roughly cylindrical. Thevertebral body has a superior surface that is concave transversely andconvex antero-posterioly with prominent elevations on each side. Twoarticular facets on the inferior surface of the body articulate with theuncinate processes. Additionally, the posterior arch is formed by thepedicles, the articular processes, the laminae and the spinousprocesses. The vertebral pedicles are short and thick regions projectingbackwards and slightly laterally from the vertebral body. The articularprocesses are located at the junction of the pedicles and laminae andare made up of the superior articular process that articulates with theabove vertebra and the inferior articular process that articulates withthe vertebra below it. The laminae are long and thin, extendingbackwards and medially from the pedicle to meet the midline therebycompleting the posterior arch. The spinous processes project backwardsfrom the junction of the laminae. Transverse processes arise anteriorlyfrom the vertebral body and posteriorly from the articular processes toform the vertebral foramen. The vertebral foramen is the triangularregion occupied by the spinal cord, meninges and associated vessels.Additionally, the vertebrae cephalad to the sacral vertebrae are unitedby articular capsules and by ligaments and separated byfibrocartilaginous intervertebral discs. The outside surface of thevertebral body is made of a relatively strong cortical bone layer, whilethe center of the vertebral body is made of a weak cancellous bone.

The vertebral bodies are separated by intervertebral discs, whichprovide the majority of the weight bearing support of the vertebralcolumn. The intervertebral discs include a cartilage shell enclosing acentral mass that provides cushioning and dampening of compressiveforces applied to the vertebral bodies and the spinal column. Generally,the central mass is relatively inelastic, but can bulge outward toaccommodate loads applied axially to the spinal.

The successive positioning of the vertebral body allows the vertebralforamen to surround the spinal cord and retain articulation of thevertebrae and extend posteriorly of the spinal canal. The complicatedvertebral structure, the degree of spinal articulation and complicatednetwork of connective elements make the spine susceptible to many formsof damage, e.g., traumatic spinal injuries, tumors, infections,surgeries, disease processes, aging processes, and congenitalabnormalities. Various types of spinal column disorders are known andinclude degenerative disc disease, excess lordosis (abnormal backwardcurvature of the spine), fractured vertebra, kyphosis (abnormal forwardcurvature of the spine), ruptured discs, scoliosis (abnormal lateralcurvature of the spine), slipped discs, spondylolisthesis (abnormalforward displacement of vertebra) and the like.

The discs of the present invention may be fabricated from generallybiocompatible materials including, without limitation, titanium,surgical alloys, stainless steel, chrome-molybdenum alloy, cobaltchromium alloy, zirconium oxide ceramic, non-absorbable polymers andother anticipated biocompatible metallic, ceramic or polymeric materialsand combinations thereof. The discs may be fabricated from differentmaterials and may even be fabricated by using different materials withineach disc. Certain materials may even be used to coat a portion or allof a disc, e.g., a titanium disc may be fused, welded, melted, coated,impregnated or infused along it's a portion or all of its periphery witha ceramic or a polymer. Alternatively, the fused, welded, melted,coated, impregnated or infused material may be on a portion or all ofone surface but not another, or, may completely surround the disc.

The components of the present invention may be constructed from anysuitable similar or dissimilar materials (e.g., titanium, a titaniumalloy, a metal, an alloy, a stainless steel, a composite, a polymer, ablend of polymers, a carbon fiber, a plastic, a thermoplastic, aceramic, carbon nanotubes, a synthetic material or other material knownto the skilled artisan) depending on the particular need or application.In addition combinations and mixtures of material may be used, e.g.,ceramic coated metal, carbon nanotube coated metal and/or ceramic,polymer coated metal and/or ceramic, a magnetic material combined with apolymer, an electrical conductive material combined with a polymer,metal, plastic, etc. and so-forth. For example, polymers and manylightweight and remarkably strong materials that include a reinforcedtwo-phase material, carbon fiber reinforced plastic, carbon fiber,plastic, polymers or combinations thereof. Polymers such as silicone,polyethylene, nylon, vinyl, methylmethacyrate, dacrons or teflon may beused. The screws may be made of a strong material (e.g., metal,magnamite graphite fiber, carbon reinforced plastic) so as to preventthe screws from being sheared off by the stress of the system.Additionally, porous material in which the porosity is controlled by thereplamine form process may be used. The materials used are not limitedto the above noted and may also include other suitable solid materialsthat have the above-noted properties.

The figures depict specific embodiments of the present invention used asan artificial spinal disc replacement. As will be disclosed in detailherein, the present invention will have wide applicability to a numberof different locations and for replacement of many different types ofjoints. The artificial spinal prosthesis depicted in the figures arenon-limiting examples of the present invention. In addition the presentinvention includes embodiments that are used in other locations in thebody and various cages. The variable angle attachment mechanism of thepresent invention may be used in various medical devices known to theskilled artisan.

FIG. 1A is an image of the intervertebral disc endoprosthesis inoperation 10. The image illustrates two vertebrae, superior vertebra 12and inferior vertebra 14 of the spine separated by a gap 16 showingeroded region 18. The intervertebral disc endoprosthesis 20 ispositioned in the gap 16 and secured to the superior vertebra 12 andinferior vertebra 14 using fasteners 22 a and 22 b. The superiorvertebra 12 has an inferior surface 24 depicted as planar, or flat, soas to optimize the substantially complementary upper surface 28 of thedisc endoprosthesis 20. The inferior vertebra 14 has a superiorvertebral surface 30 that has a shape that is complementary to theinferior surface 32 of the disc endoprosthesis 20. Although not shown,the musculature and other body tissues normally surround the spinalcolumn around the disc endoprosthesis 20 and the superior vertebra 12and inferior vertebra 14. A wide variety of mechanical attachmentsmethods and hardware may be used ensure that the components of the discendoprosthesis 20 remain in place for the duration of their use. By wayof example and without limitation, mechanical attachment may include ascrew, nail, rivet, adhesive, wire, band, strap, and embodiments forporous coating of the prosthesis endplate screws or the combination andlocking mechanisms to affix the screw to the disc endoprosthesis 20. Thedisc endoprosthesis 20 may be adapted to receive and retain screws,nails, rivets, spikes and other articles used to secure the discendoprosthesis 20 to adjacent vertebra without protruding from thesurface of the discs to cause friction. For example, the intervertebraldisc endoprosthesis 20 may include countersunk fastener 22 or can havelocking methods or mechanisms that stabilize a screw (fasteners 22 a and22 b) to the disc endoprosthesis 20.

FIG. 1B is an image of the intervertebral disc endoprosthesis inoperation 10 illustrating the need for a steeper insertion angle as aresult of the smaller vertebra. The image illustrates two vertebrae,superior vertebra 12 and inferior vertebra 14 of the spine separated bya gap 16 showing eroded region 18. The intervertebral discendoprosthesis 20 is positioned in the gap 16 and secured to thesuperior vertebra 12 and inferior vertebra 14 using fasteners 22 a and22 b. The superior vertebra 12 has an inferior surface 24 depicted asplanar, or flat, so as to optimize the substantially complementary uppersurface 28 of the disc endoprosthesis 20. The inferior vertebra 14 has asuperior vertebral surface 30 that has a shape that is complementary tothe inferior surface 32 of the disc endoprosthesis 20. Although notshown, the musculature and other body tissues normally surround thespinal column around the disc endoprosthesis 20 and the superiorvertebra 12 and inferior vertebra 14. A wide variety of mechanicalattachments methods and hardware may be used ensure that the componentsof the disc endoprosthesis 20 remain in place for the duration of theiruse. By way of example and without limitation, mechanical attachment mayinclude a screw, nail, rivet, adhesive, wire, band, strap, andembodiments for porous coating of the prosthesis endplate screws or thecombination and locking mechanisms to affix the screw to the discendoprosthesis 20. The disc endoprosthesis 20 may be adapted to receiveand retain screws, nails, rivets, spikes and other articles used tosecure the disc endoprosthesis 20 to adjacent vertebra withoutprotruding from the surface of the discs to cause friction. For example,the intervertebral disc endoprosthesis 20 may include countersunkfastener 22 or can have locking methods or mechanisms that stabilize ascrew (fasteners 22 a and 22 b) to the disc endoprosthesis 20.

FIG. 2 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30 an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 an inferior surface 32to separate them. The disc endoprosthesis 20 includes an anterior region36 that is generally flat and the posterior region 38 that is arched.Optionally the present invention may have a recess 40 having an archedparameter 42 that extends to form the recess 40 in some embodiments therecess 40 extends through the disc endoprosthesis 20. However, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes a first anteriorcavity 44 a formed by a first cavity width 46 a and a first cavitylength 48 a relative to the first bridge 50 and the middle bridge 52.The first anterior cavity 44 a may include a first tapered region 54 aextending toward the anterior region 36. The anterior region 36 alsoincludes a second anterior cavity 44 b formed by a second cavity width46 b and a second cavity length 48 b relative to the second bridge 56and the middle bridge 52. The second anterior cavity 44 b may include asecond tapered region 54 b extending toward the anterior region 36. Afirst insert 58 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52and away from the anterior region 36 toward the first tapered region 54a. The first insert 58 a includes a first insert aperture 60 a extendingthrough the first insert 58 a to accept a fastener (not shown) andincluding a first insert taper 62 a to allow the fastener (not shown) tobe recessed into the first insert 58 a. A second insert 58 b isrotatably positioned within the second anterior cavity 44 b extendingfrom the second bridge 56 to the middle bridge 52 and away from theanterior region 36 toward the second tapered region 54 b. The secondinsert 58 b includes a second insert aperture 60 b extending through thesecond insert 58 b to accept a fastener (not shown) and including asecond insert taper 62 b to allow the fastener (not shown) to berecessed into the second insert 58 b. The second insert 58 b may besecured in the second anterior cavity 44 b and rotatable through themating of a securing peg 64 and a securing aperture 66.

The recess 40 forms a cavity for inserting bone graph material. In someembodiments the cavity extends through the disc endoprosthesis 20.However, other embodiments may be a cavity or an indention on one orboth sides depending on the particular application. In addition therecess 40 may be of a variety of sizes, depths and shapes. Regardless ofthe actual parameters of the recess 40, the skilled artisan willunderstand that bone graph materials and/or materials that support orenhance bone graphing may be in the recess 40. For example, the bonegraft material serves as a scaffold for new bone growth that isperpetuated by the native bone; osteoprogenitor cells can be stimulatedto differentiate into osteoblasts that then begin new bone formation.Osteopromotion may also be used, e.g., the enhancement of osteoinductionwithout the possession of osteoinductive properties. For example, enamelmatrix derivative has been shown to enhance the osteoinductive effect ofdemineralized freeze dried bone allograft (DFDBA), but will notstimulate de novo bone growth alone. The material may be an autologous(or autogenous) bone grafting involves utilizing bone obtained from thesame individual receiving the graft. Bone can be harvested fromnon-essential bones, such as from the iliac crest, or more commonly inoral and maxillofacial surgery, from the mandibular symphysis (chinarea) or anterior mandibular ramus (the coronoid process). Allograftbone, like autogenous bone, is derived from humans; the difference isthat allograft is harvested from an individual other than the onereceiving the graft. Types of bone allograft includes fresh orfresh-frozen bone, freeze-dried bone allograft (FDBA), and demineralizedfreeze-dried bone allograft (DFDBA). In addition, artificial bonematerial can be used, e.g., ceramics such as calcium phosphates (e.g.hydroxyapatite and tricalcium phosphate), Bioglass and calcium sulphate;all of which are biologically active to different degrees depending onsolubility in the physiological environment. These materials can bedoped with growth factors, ions such as strontium or mixed with bonemarrow aspirate to increase biological activity. Xenografts including acalcified matrix may be used. Alloplastic grafts may be made fromhydroxylapatite. Some synthetic bone grafts are made of calciumcarbonate or tricalcium phosphate and in combination withhydroxylapatite. In addition the recess 40 may include one or morefactors to enhance and stimulate the growth of bones, e.g., a growthFactor enhanced graft, e.g., Human Growth Factors or Morphogens (BoneMorphogenic Proteins in conjunction with a carrier medium, such ascollagen).

FIG. 3 is a top view of an image of the intervertebral discendoprosthesis 20 of the present invention. The disc endoprosthesis 20includes a superior vertebral surface 30 an inferior surface (not shown)and a side surface (not shown) that extends between the superiorvertebral surface 30 an inferior surface (not shown) to separated them.The disc endoprosthesis 20 includes an anterior region 36 that isgenerally flat and the posterior region 38 that is arched. Optionallythe present invention may have a recess 40 having an arched parameter 42that extends to form the recess 40. In some embodiments, the recess 40extends through the disc endoprosthesis 20; however, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes a first anteriorcavity 44 a formed by a first cavity width 46 a and a first cavitylength 48 a relative to the first bridge 50 and the middle bridge 52.The first anterior cavity 44 a may include a first tapered region 54 aextending toward the anterior region 36. The anterior region 36 alsoincludes a second anterior cavity 44 b formed by a second cavity width46 b and a second cavity length 48 b relative to the second bridge 56and the middle bridge 52. The second anterior cavity 44 b may include asecond tapered region 54 b extending toward the anterior region 36. Afirst insert 58 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52and away from the anterior region 36 toward the first tapered region 54a. The first insert 58 a includes a first insert aperture (not shown)extending through the first insert 58 a to accept a fastener (not shown)and including a first insert taper 62 a to allow the fastener (notshown) to be recessed into the first insert 58 a. A second insert 58 bis rotatably positioned within the second anterior cavity 44 b extendingfrom the second bridge 56 to the middle bridge 52 and away from theanterior region 36 toward the second tapered region 54 b. The secondinsert 58 b includes a second insert aperture (not shown) extendingthrough the second insert 58 b to accept a fastener (not shown) andincluding a second insert taper 62 b to allow the fastener (not shown)to be recessed into the second insert 58 b. The second insert 58 b maybe secured in the second anterior cavity 44 b and rotatable through themating of a securing peg (not shown) and securing aperture (not shown).

FIG. 4 is an image of the intervertebral disc endoprosthesis inoperation 10 of the present invention in operation. The imageillustrates two superior vertebra 12 and inferior vertebra 14 of thespine separated by a gap 16 showing eroded region 18. The intervertebraldisc endoprosthesis 20 is positioned in the gap 16 and secured to thesuperior vertebra 12 and inferior vertebra 14 using fasteners 22 a and22 b. The superior vertebra 12 has an inferior surface 24 depicted asplanar, or flat, so as to optimize the substantially complementary uppersurface 28 of the disc endoprosthesis 20. The inferior vertebra 14 has asuperior vertebral surface 30 that has a shape that is complementary tothe inferior surface 32 of the disc endoprosthesis 20. For example, theintervertebral disc endoprosthesis 20 the first insert (not shown)having a first insert aperture (not shown) extending through the firstinsert (not shown) to accept a first fastener 22 a and including a firstinsert taper (not shown) to allow the fastener 22 a to be recessed intothe first insert (not shown). A second insert (not shown) is rotatablypositioned within the second anterior cavity (not shown) extending fromthe second bridge (not shown) to the middle bridge (not shown) and awayfrom the anterior region 36 toward the second tapered region (notshown). The second insert 58 b includes a second insert aperture 60 bextending through the second insert 58 b to accept a fastener (notshown) and including a second insert taper 62 b to allow the fastener(not shown) to be recessed into the second insert 58 b. Theintervertebral disc endoprosthesis 20 includes a first and a secondcountersunk fastener 22 a and 22 b to secure the intervertebral discendoprosthesis 20 to the disc endoprosthesis 20 depicted in FIG. 1.

FIG. 5 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30 an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 an inferior surface 32to separate them. The disc endoprosthesis 20 includes an anterior region36 that is generally flat and the posterior region 38 that is arched.Optionally the present invention may have a recess 40 having an archedparameter 42 that extends to form the recess 40 in some embodiments therecess 40 extends through the disc endoprosthesis 20. However, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes a first anteriorcavity 44 a formed by a first cavity width 46 a and a first cavitylength 48 a relative to the first bridge 50, the middle bridge 52 andthe first tapered region edge 68 a. The first anterior cavity 44 a mayinclude a first tapered region 54 a extending toward the anterior region36. The anterior region 36 also includes a second anterior cavity 44 bformed by a second cavity width 46 b and a second cavity length 48 brelative to the second bridge 56 and the middle bridge 52. The secondanterior cavity 44 b may include a second tapered region 54 b extendingtoward the anterior region 36. A first insert 58 a having a first insertarched surface 70 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52.The first insert 58 a includes a first insert first tongue 72 a thatmates to a first bridge groove 74 a positioned in the first bridge 50and a first insert second tongue 72 b. The first insert 58 a includes afirst insert aperture (not shown) extending through the first insert(not shown) to accept a fastener (not shown) and including a firstinsert taper (not shown) to allow the fastener (not shown) to berecessed into the first insert 58 a. A second insert 58 b is rotatablypositioned within the second anterior cavity 44 b extending from thesecond bridge 56 to the middle bridge 52 and away from the anteriorregion 36 toward the second tapered region 54 b to the second taperedregion edge 68 b. The second insert 58 b includes a second insert groove76 that mates to the first insert second tongue 72 b of the first insert58 a and a second insert first tongue 72 b that mates to a second bridgegroove 78 positioned in the second bridge 56. The second insert 58 bincludes a second insert aperture 60 b extending through the secondinsert 58 b to accept a fastener (not shown) and including a secondinsert taper 62 b to allow the fastener (not shown) to be recessed intothe second insert 58 b.

FIG. 6 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30 an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 an inferior surface 32to separate them. The disc endoprosthesis 20 includes an anterior region36 that is generally flat and the posterior region 38 that is arched.Optionally the present invention may have a recess 40 having an archedparameter 42 that extends to form the recess 40 in some embodiments therecess 40 extends through the disc endoprosthesis 20. However, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes a first anteriorcavity 44 a formed by a first cavity width 46 a and a first cavitylength 48 a relative to the first bridge 50 and the middle bridge 52.The first anterior cavity 44 a may include a first tapered region 54 aextending toward the anterior region 36. The anterior region 36 alsoincludes a second anterior cavity 44 b formed by a second cavity width46 b and a second cavity length 48 b relative to the second bridge 56and the middle bridge 52. The second anterior cavity 44 b may include asecond tapered region 54 b extending toward the anterior region 36. Afirst insert 58 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52and away from the anterior region 36 toward the first tapered region 54a. The first insert 58 a includes a first insert aperture 60 a extendingthrough the first insert 58 a to accept a fastener (not shown) andincluding a first insert taper 62 a to allow the fastener (not shown) tobe recessed into the first insert 58 a. A second insert 58 b isrotatably positioned within the second anterior cavity 44 b extendingfrom the second bridge 56 to the middle bridge 52 and away from theanterior region 36 toward the second tapered region 54 b. The secondinsert 58 b includes a second insert aperture 60 b extending through thesecond insert 58 b to accept a fastener (not shown) and including asecond insert taper 62 b to allow the fastener (not shown) to berecessed into the second insert 58 b. The second insert 58 b may besecured in the second anterior cavity 44 b and rotatable through themating of a securing peg 64 and a securing aperture 66. The first insert58 a and the second insert 58 b include first insert indicia 80 a andsecond insert indicia 80 b used to align or reference the first bridgeindicia 82 a and second bridge indicia 82 b on the first bridge 50 andthe second bridge 56. In addition, the securing peg 64 may includesecuring peg indicia 84 and the securing aperture 66 may include thecorresponding securing aperture indicia 86 that may be used foralignment or reference.

FIG. 7 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30 an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 an inferior surface 32to separate them. The disc endoprosthesis 20 includes an anterior region36 that is generally flat and the posterior region 38 that is arched.Optionally, the present invention may have an recess 40 having an archedparameter 42 that extends to form the recess 40 in some embodiments therecess 40 extends through the disc endoprosthesis 20. However, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes a first anteriorcavity 44 a formed by a first cavity width 46 a and a first cavitylength 48 a relative to the first bridge 50 and the middle bridge 52.The first anterior cavity 44 a may include a first tapered region 54 aextending toward the anterior region 36. The anterior region 36 alsoincludes a second anterior cavity 44 b formed by a second cavity width46 b and a second cavity length 48 b relative to the second bridge 56and the middle bridge 52. The second anterior cavity 44 b may include asecond tapered region 54 b extending toward the anterior region 36. Afirst insert 58 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52and away from the anterior region 36 toward the first tapered region 54a. The first insert 58 a includes a first insert aperture 60 a extendingthrough the first insert 58 a to accept a fastener (not shown) andincluding a first insert taper 62 a to allow the fastener (not shown) tobe recessed into the first insert 58 a. A second insert 58 b isrotatably positioned within the second anterior cavity 44 b extendingfrom the second bridge 56 to the middle bridge 52 and away from theanterior region 36 toward the second tapered region 54 b. The secondinsert 58 b includes a second insert aperture 60 b extending through thesecond insert 58 b to accept a fastener (not shown) and including asecond insert taper 62 b to allow the fastener (not shown) to berecessed into the second insert 58 b. The second insert 58 b may besecured in the second anterior cavity 44 b and rotatable through thesecuring peg 64 a, 64 b, 64 c, and 64 d. The first insert 58 a and thesecond insert 58 b may be smaller than the corresponding first anteriorcavity 44 a and second anterior cavity 44 b to provide the insert gaps88 a, 88 b, 88 c, and 88 d.

FIG. 8 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30 an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 an inferior surface 32to separate them. The disc endoprosthesis 20 includes an anterior region36 that is generally flat and the posterior region 38 that is arched.Optionally the present invention may have a recess 40 having an archedparameter 42 that extends to form the recess 40 in some embodiments therecess 40 extends through the disc endoprosthesis 20. However, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes an anterior surface90 and an first anterior cavity 44 formed by a first cavity width 46 anda first cavity length 48. The first anterior cavity 44 may include afirst tapered region 92 extending toward the anterior region 36. Theanterior surface 90 includes a first insert aperture 60 a extendingthrough the first insert 58 a to accept a fastener (not shown) andincluding a first insert taper 62 a and a second insert taper 62 b toallow the fasteners (not shown) to be recessed.

FIG. 9 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30 an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 an inferior surface 32to separate them. The disc endoprosthesis 20 includes an anterior region36 that is generally flat and the posterior region 38 that is arched.Optionally the present invention may have an recess 40 having an archedparameter 42 that extends to form the recess 40 in some embodiments therecess 40 extends through the disc endoprosthesis 20. However, in otherembodiments the recess 40 is extends partially through the discendoprosthesis 20 or creates an indention (not shown) into the discendoprosthesis 20. The anterior region 36 includes a first anteriorcavity 44 a formed by a first cavity width 46 a and a first cavitylength 48 a relative to the first bridge 50 and the middle bridge 52.The first anterior cavity 44 a may include a first tapered region 54 aextending toward the anterior region 36. The anterior region 36 alsoincludes a second anterior cavity 44 b formed by a second cavity width46 b and a second cavity length 48 b relative to the second bridge 56and the middle bridge 52. The second anterior cavity 44 b may include asecond tapered region 54 b extending toward the anterior region 36. Afirst insert 58 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52and away from the anterior region 36 toward the first tapered region 54a. The first insert 58 a includes a first insert aperture 60 a extendingthrough the first insert 58 a to accept a fastener (not shown) andincluding a first insert taper 62 a to allow the fastener (not shown) tobe recessed into the first insert 58 a. The first insert 58 a includes afirst insert grooved region 94 a that mate to first insert aperturegrooves 96 a to provide resistance. A second insert 58 b is rotatablypositioned within the second anterior cavity 44 b extending from thesecond bridge 56 to the middle bridge 52 and away from the anteriorregion 36 toward the second tapered region 54 b. The second insert 58 bincludes a second insert grooved region 94 b that mate to second insertaperture grooves 96 b to provide resistance. The second insert 58 bincludes a second insert aperture 60 b extending through the secondinsert 58 b to accept a fastener (not shown) and including a secondinsert taper 62 b to allow the fastener (not shown) to be recessed intothe second insert 58 b. The second insert 58 b may be secured in thesecond anterior cavity 44 b and rotatable through the securing peg 64 a,64 b, 64 c, and 64 d that mate to the corresponding peg aperture 98 aand 98 c. The first insert 58 a and the second insert 58 b may besmaller than the corresponding first anterior cavity 44 a and secondanterior cavity 44 b to provide the insert gaps 88 a, 88 b, 88 c, and 88d.

FIG. 10 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30, an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 and inferior surface32 to separate them. The disc endoprosthesis 20 includes an anteriorregion 36 that is generally flat and the posterior region 38 that isarched. Optionally, the present invention may have a recess 40 having anarched parameter 42 that extends to form the recess 40. In someembodiments, the recess 40 extends through the disc endoprosthesis 20.However, in other embodiments, the recess 40 is extended partiallythrough the disc endoprosthesis 20 or creates an indention (not shown)into the disc endoprosthesis 20. The anterior region 36 includes a firstanterior cavity 44 a formed by a first cavity width 46 a and a firstcavity length 48 a relative to the first bridge 50 and the middle bridge52. The first anterior cavity 44 a may include a first tapered region 54a extending toward the anterior region 36. The anterior region 36 alsoincludes a second anterior cavity 44 b formed by a second cavity width46 b and a second cavity length 48 b relative to the second bridge 56and the middle bridge 52. The second anterior cavity 44 b may include asecond tapered region 54 b extending toward the anterior region 36. Afirst insert 58 a is rotatably positioned within the first anteriorcavity 44 a extending from the first bridge 50 to the middle bridge 52and away from the anterior region 36 toward the first tapered region 54a. The first insert 58 a includes a first insert aperture 60 a extendingthrough the first insert 58 a to accept a fastener (not shown) andincluding a first insert taper 62 a to allow the fastener (not shown) tobe recessed into the first insert 58 a. The first insert 58 a includes afirst insert textured region 100 a that mates to the first insertaperture textured region 102 a to provide resistance. A second insert 58b is rotatably positioned within the second anterior cavity 44 bextending from the second bridge 56 to the middle bridge 52 and awayfrom the anterior region 36 toward the second tapered region 54 b. Thesecond insert 58 b includes a second insert textured region 100 b thatmates to the second insert aperture textured region 102 b to provideresistance. The second insert 58 b includes a second insert aperture 60b extending through the second insert 58 b to accept a fastener (notshown) and including a second insert taper 62 b to allow the fastener(not shown) to be recessed into the second insert 58 b. The secondinsert 58 b may be secured in the second anterior cavity 44 b androtatable through the securing peg 64 a, 64 b, 64 c, and 64 d that mateto the corresponding peg aperture 98 a and 98 c. The first insert 58 aand the second insert 58 b may be smaller than the corresponding firstanterior cavity 44 a and second anterior cavity 44 b to provide theinsert gaps 88 a, 88 b, 88 c, and 88 d.

FIG. 11 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30, an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 and inferior surface32 to separate them. The disc endoprosthesis 20 includes an anteriorregion 36 that is generally flat and the posterior region 38 that isarched. Optionally, the present invention may have a recess 40 having anarched parameter 42 that extends to form the recess 40. In someembodiments, the recess 40 extends through the disc endoprosthesis 20.However, in other embodiments, the recess 40 is extends partiallythrough the disc endoprosthesis 20 or creates an indention (not shown)into the disc endoprosthesis 20. The anterior region 36 includes ananterior surface 90 and a first anterior cavity 44 formed by a firstcavity width 46 and a first cavity length 48. The first anterior cavity44 may include a first tapered region 92 extending toward the anteriorregion 36. The anterior surface 90 includes a first insert aperture 60 ahaving a first insert taper 62 a and a second insert aperture 60 b witha second insert taper 62 b to accept a first insert jacket 104 a withfirst jacket textured region 106 a to fit into first insert aperture 60a with first textured region 108 a and a second insert jacket 104 b withsecond jacket textured region 106 b to fit into the second insertaperture 60 b having the second textured region 108 b.

FIG. 12 is an image of the intervertebral disc endoprosthesis 20 of thepresent invention. The disc endoprosthesis 20 includes a superiorvertebral surface 30, an inferior surface 32 and a side surface 34 thatextends between the superior vertebral surface 30 and inferior surface32 to separate them. The disc endoprosthesis 20 includes an anteriorregion 36 that is generally flat and the posterior region 38 that isarched. Optionally the present invention may have a recess 40 having anarched parameter 42 that extends to form the recess 40. In someembodiments, the recess 40 extends through the disc endoprosthesis 20.However, in other embodiments, the recess 40 is extends partiallythrough the disc endoprosthesis 20 or creates an indention (not shown)into the disc endoprosthesis 20. The anterior region 36 includes ananterior surface 90 and a first anterior cavity 44 formed by a firstcavity width 46 and a first cavity length 48. The first anterior cavity44 may include a first tapered region 92 extending toward the anteriorregion 36. The anterior surface 90 includes a first insert aperture 60 aincluding a first insert taper 62 a and a second insert aperture 60 bwith a second insert taper 62 b to accept a first insert jacket 104 awith first jacket textured region 106 a to fit into first insertaperture 60 a with first textured region 108 a and a second insertjacket 104 b with second jacket textured region 106 b to fit into thesecond insert aperture 60 b having the second textured region 108 b.

FIG. 13 is an image of the vertebral prosthesis 120 of the presentinvention. The vertebral prosthesis 120 includes 3 attachment fixtures122 a, 122 b and 122 c connected by connecting members 124 a and 124 b.The attachment fixture 122 a includes a vertebral contacting surface 126a to attach to a vertebral surface (not shown). The attachment fixture122 a includes an anterior region 126 a and the posterior region 128 athat is also generally flat. The anterior region 126 a includes a firstanterior cavity 130 a between a first bridge 138 a and the middle bridge134 a. A first insert 140 a is rotatably positioned within the firstanterior cavity 130 a extending from the first bridge 132 a to themiddle bridge 134 a. The first insert 140 a includes a first insertaperture 142 a extending through the first insert 140 a to accept afastener (not shown) and including a first insert taper 144 a to allowthe fastener (not shown) to be recessed into the first insert 140 a. Asecond insert 146 a is rotatably positioned within the second anteriorcavity 136 a extending from the second bridge 138 a to the middle bridge134 a. The second insert 146 a includes a second insert aperture 148 aextending through the second insert 146 a to accept a fastener (notshown) and including a second insert taper 150 a to allow the fastener(not shown) to be recessed into the second insert 146 a. The secondinsert 146 a may be secured in the second anterior cavity 136 a androtatable through the mating of a securing peg 152 a and a securingaperture 154 a. The attachment fixture 122 b includes a vertebralcontacting surface 126 b to attach to a vertebral surface (not shown).The attachment fixture 122 b includes an anterior region 126 b and theposterior region 128 b, that is also generally flat. The anterior region126 b includes a first anterior cavity 130 b between a first bridge 138b and the middle bridge 134 b. A first insert 140 b is rotatablypositioned within the first anterior cavity 130 b extending from thefirst bridge 132 b to the middle bridge 134 b. The first insert 140 bincludes a first insert aperture 142 b extending through the firstinsert 140 b to accept a fastener (not shown) and including a firstinsert taper 144 b to allow the fastener (not shown) to be recessed intothe first insert 140 b. A second insert 146 b is rotatably positionedwithin the second anterior cavity 136 b extending from the second bridge138 b to the middle bridge 134 b. The second insert 146 b includes asecond insert aperture 148 b extending through the second insert 146 bto accept a fastener (not shown) and including a second insert taper 150b to allow the fastener (not shown) to be recessed into the secondinsert 146 b. The second insert 146 b may be secured in the secondanterior cavity 136 b and rotatable through the mating of a securing peg152 b and a securing aperture 154 b. The attachment fixture 122 cincludes a vertebral contacting surface 126 c to attach to a vertebralsurface (not shown). The attachment fixture 122 c includes an anteriorregion 126 c and the posterior region 128 c that is also generally flat.The anterior region 126 c includes a first anterior cavity 130 c betweena first bridge 138 c and the middle bridge 134 c. A first insert 140 cis rotatably positioned within the first anterior cavity 130 c extendingfrom the first bridge 132 c to the middle bridge 134 c. The first insert140 c includes a first insert aperture 142 c extending through the firstinsert 140 c to accept a fastener (not shown) and including a firstinsert taper 144 c to allow the fastener (not shown) to be recessed intothe first insert 140 c. A second insert 146 c is rotatably positionedwithin the second anterior cavity 136 c extending from the second bridge138 c to the middle bridge 134 c. The second insert 146 c includes asecond insert aperture 148 c extending through the second insert 146 cto accept a fastener (not shown) and including a second insert taper 150c to allow the fastener (not shown) to be recessed into the secondinsert 146 c. The second insert 146 c may be secured in the secondanterior cavity 136 c and rotatable through the mating of a securing peg152 c and a securing aperture 154 c.

FIG. 14 is an image of the vertebral prosthesis 120 of the presentinvention in operation. The vertebral prosthesis 120 includes 3attachment fixtures 122 a, 122 b and 122 c connected by a connectingmembers 124 a and 124 b and attached to 3 vertebras 156 a, 156 b and 156c. The attachment fixture 122 a, 122 b and 122 c includes a vertebralcontacting surface 126 a, 126 b and 126 c to attach to a vertebralsurface. The attachment fixtures 122 a, 122 b and 122 c are attached tothe vertebra 156 a, 156 b and 156 c with the connecting members 124 aand 124 b spanning the gaps occupied by disks 158 a and 158 b.

The attachment fixtures 122 a includes an anterior region 160 a with afirst insert (not shown) rotatably positioned within the first anteriorcavity (not shown) extending from the first bridge (not shown) to themiddle bridge (not shown). The first insert (not shown) includes a firstinsert aperture (not shown) extending through the first insert (notshown) to accept fastener 162 a. A second insert (not shown) isrotatably positioned within the second anterior cavity (not shown)extending from the second bridge (not shown) to the middle bridge (notshown). The second insert (not shown) includes a second insert aperture(not shown) extending through the second insert (not shown) to accept afastener 164 a. The second insert (not shown) may be secured in thesecond anterior cavity (not shown) and rotatable through the mating of asecuring peg (not shown) and a securing aperture (not shown).

The attachment fixture 122 b includes an anterior region 160 b with afirst insert (not shown) is rotatably positioned within the firstanterior cavity (not shown) extending from the first bridge (not shown)to the middle bridge (not shown). The first insert (not shown) includesa first insert aperture (not shown) extending through the first insert(not shown) to accept fastener 162 b. A second insert (not shown) isrotatably positioned within the second anterior cavity (not shown)extending from the second bridge (not shown) to the middle bridge (notshown). The second insert (not shown) includes a second insert aperture(not shown) extending through the second insert (not shown) to accept afastener 164 b. The second insert (not shown) may be secured in thesecond anterior cavity (not shown) and rotatable through the mating of asecuring peg (not shown) and a securing aperture (not shown).

The attachment fixture 122 c includes an anterior region 160 c with afirst insert (not shown) is rotatably positioned within the firstanterior cavity (not shown) extending from the first bridge (not shown)to the middle bridge (not shown). The first insert (not shown) includesa first insert aperture (not shown) extending through the first insert(not shown) to accept fastener 162 c. A second insert (not shown) isrotatably positioned within the second anterior cavity (not shown)extending from the second bridge (not shown) to the middle bridge (notshown). The second insert (not shown) includes a second insert aperture(not shown) extending through the second insert (not shown) to accept afastener 164 c. The second insert (not shown) may be secured in thesecond anterior cavity (not shown) and rotatable through the mating of asecuring peg (not shown) and a securing aperture (not shown).

FIG. 15 is an image of a screw used in the present invention. Thefasteners 22 may be any type of fastener that the skilled artisan mayuse to secure to a bone and include various thread patterns andspacings. In addition, the fastener may be constructed from materialsknown to the skilled artisan and used in the field and include coatingsto promote growth of bone and/or reduce infection (e.g., HA coating). Inone embodiment, the fastener 22 is a screw 180 that includes a screwhead 182 used to fit and secure the fastener 22 to the attachmentfixture (not shown). The screw head 182 is sized and shaped to contactthe aperture of the attachment fixture (not shown). In communication,with the screw head 182 is a first set of threads 184 that are designedto mate to the attachment fixture (not shown) threads to secure thefastener 22 to the attachment fixture (not shown) and contact of thescrew head 182 to the attachment fixture (not shown). The first set ofthreads 184 are in communication with a second set of threads 186 thatare designed to penetrate bone and secure the fastener 22 to the bone.The screw head 182 is designed to be larger than the aperture in theattachment fixture (not shown) so as not to pass through the attachmentfixture (not shown) but secure the fastener 22 to the attachment fixture(not shown). The first set of threads 184 are designed to be smallerthan the screw head 182 and designed to mate to the threads of theaperture in the attachment fixture (not shown) to secure the fastener 22to the attachment fixture (not shown). The second set of threads 186 aredesigned to be smaller than the aperture in the attachment fixture (notshown) so as to pass through the attachment fixture (not shown) into thebone (not shown).

The attachment fixture may be of a size slightly larger or smaller asnecessary to accommodate the size of the individual. The presentinvention may be made in part or whole from materials or combinations ofmaterials that provide sufficient strength and flexibility, whileremaining bio-compatible, e.g., metals, nonmetals, rubbers, plastics,vinyls, polymers, composites, non-reinforced biocompatible polymers,two-phase biocompatible polymers, plastics reinforced with dissimilarpolymers, filaments and combinations thereof.

In addition the device of the present invention may be positionedbetween the vertebrae at different positions as necessary given thespecific application. This positioning is accomplished by the ability ofthe insert to rotate. This rotation allows the angle of the screw to bevaried as needed to position the insert between the vertebrae. Forexample, insert may be positioned deeply between the vertebrae and therotation allows the screws to be inserted into the vertebrae withoutprotruding or damaging the vertebrae.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the invention, and vice versa. Furthermore, compositionsof the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, MB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and/or methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined by theappended claims.

What is claimed is:
 1. A method of stabilizing a two or more vertebracomprising the steps of: positioning an intervertebral endoprosthesisbetween two vertebrae, wherein the intervertebral endoprosthesisincludes: an endoprosthesis body including an anterior region and aposterior region designed to be positioned between a first vertebra anda second vertebra, at least a first anterior cavity and a secondanterior cavity positioned in the anterior region, a first movableinsert having a first fastener aperture and positioned rotatably in thefirst anterior cavity, wherein the first movable insert is rotatable inthe first anterior cavity, and a second movable insert having a secondfastener aperture and positioned rotatably in the second anteriorcavity, wherein the second movable insert is rotatable in the secondanterior cavity independent of the first movable insert; inserting afirst fastener through the first fastener aperture; adjusting a firstinsertion angle of a first fastener extending through the first fasteneraperture by rotating the first movable insert; inserting the firstfastener into the first vertebra; securing a second fastener through thesecond fastener aperture; adjusting a second insertion angle of thesecond fastener extending through the second fastener aperture byrotating the second movable insert; and securing a second fastenerthrough the second fastener aperture.
 2. The method of claim 1, whereinthe endoprosthesis further includes a first tapered region taperingtoward the first anterior cavity and a second tapered region taperingtoward the second anterior cavity to allow a steeper insertion angle. 3.The method of claim 1, wherein the first movable insert and the secondmovable insert are cylindrical inserts.
 4. The method of claim 1,wherein the first movable insert and the second movable insert arecylindrical that are smaller in length than the first and secondanterior cavity to allow lateral motion in addition to rotationalmovement.
 5. The method of claim 1, further comprising an aperture inthe posterior region.
 6. The method of claim 5, wherein theendoprosthesis further includes one or more components to promote bonegrowth.
 7. A method of stabilizing a two or more vertebra comprising thesteps of: positioning a surgical cage between two vertebrae, wherein thesurgical cage includes: a body that may be secured to a vertebra with asurgical screw; a first structure within the body for increasing anangle at which a first surgical screw may be screwed into a vertebrathat is adjacent to a top the body; and a second structure within thebody for increasing an angle at which a second surgical screw may bescrewed into a vertebra that is adjacent to a bottom the body.
 8. Themethod of claim 7, wherein the first structure includes: portions thatdefine an aperture through the first structure for receiving the firstsurgical screw; the second structure includes portions that define anaperture through the second structure for receiving the second surgicalscrew; a portion of the body that defines apertures through the body forreceiving the first structure and the second structure; wherein thefirst structure is rotatably mounted with respect to the body to allowthe aperture though the first structure to be rotated to increase anangle at which the first surgical screw may be screwed into the vertebrathat is adjacent to the top of the body, and wherein the secondstructure is rotatably mounted with respect to the body to allow theaperture though the second structure to be rotated to increase an angleat which the second surgical screw may be screwed into the vertebra thatis adjacent to the bottom of the body.
 9. The method of claim 8, whereinthe first structure has a length that allows the first structure to behorizontally movable back and forth along its axis of rotation and thesecond structure has a length that allows the second structure to behorizontally movable back and forth along its axis of rotation.
 10. Themethod of claim 7, wherein the first structure includes: portions thatdefine an aperture through the first structure for receiving the firstsurgical screw; and the second structure having portions that define anaperture through the second structure for receiving the second surgicalscrew.
 11. The method of claim 7, wherein the first structure includes afirst portion of the body that defines a first aperture through the bodyfor receiving the first surgical screw and a second portion of the bodythat defines a second aperture through the body that is in communicationwith the first aperture and a size of the second aperture allows thefirst surgical screw that is placed through the first aperture of thebody to be screwed into the vertebra that is adjacent to the top of thebody at an angle that is larger than would be possible if no secondaperture existed and the second structure comprises a third portion ofthe body that defines a third aperture through the body for receivingthe second surgical screw and a second portion of the body that definesthe second aperture through the body that is in communication with thethird aperture and a size of the second aperture allows the secondsurgical screw that is placed through the third aperture of the body tobe screwed into the vertebra that is adjacent to the bottom of the bodyat an angle that is larger than would be possible if no second apertureexisted.
 12. The method of claim 11 wherein the surgical cage furtherincludes: a first adapter sleeve that fits into the first aperturethrough the body to decrease a size of the first aperture; and a secondadapter sleeve that fits into the third aperture through the body todecrease a size of the third aperture.
 13. The method of claim 12,wherein the first adapter sleeve is formed with portions that define aplurality of grooves on the outer surface of the first adapter sleeveand wherein the first aperture through the body is formed with portionsthat define a plurality of grooves on the inner surface of the firstaperture to cause the first adapter sleeve to fit securely within thefirst aperture and the second adapter sleeve is formed with portionsthat define a plurality of grooves on the outer surface of the secondadapter sleeve and wherein the third aperture through the body is formedwith portions that define a plurality of grooves on the inner surface ofthe third aperture to cause the second adapter sleeve to fit securelywithin the third aperture.
 14. The method of claim 7, wherein a backportion of the first cylinder is formed with portions that define aplurality of grooves on the outer surface of the first cylinder andwherein a portion of the body that is adjacent to the back portion ofthe first cylinder is formed with portions that define a plurality ofgrooves on the inner surface of the adjacent portion of the body tocause the first cylinder to fit securely against the adjacent portion ofthe body; and wherein a back portion of the second cylinder is formedwith portions that define a plurality of grooves on the outer surface ofthe second cylinder and wherein a portion of the body that is adjacentto the back portion of the second cylinder is formed with portions thatdefine a plurality of grooves on the inner surface of the adjacentportion of the body to cause the second cylinder to fit securely againstthe adjacent portion of the body.
 15. A method of stabilizing a two ormore vertebra comprising the steps of: positioning an vertebralprosthesis across at least two vertebrae, wherein the vertebralprosthesis includes: a first attachment fixture and a second attachmentfixture each attachment fixture comprising an anterior region and aposterior region designed to be positioned on the surface of a firstvertebra, at least a first anterior cavity and a second anterior cavitypositioned in the anterior region, a first movable insert having a firstfastener aperture and positioned rotatably in the first anterior cavity,wherein the first movable insert is rotatable in the first anteriorcavity, and a second movable insert having a second fastener apertureand positioned rotatably in the second anterior cavity, wherein thesecond movable insert is rotatable in the second anterior cavityindependent of the first movable insert, wherein a first insertion angleof a first fastener extending through the first fastener aperture may beadjusted by rotating the first movable insert and a second insertionangle of a second fastener extending through the second fasteneraperture may be adjusted by rotating the second movable insert; and anstabilization body attached to the first and the second attachmentfixtures to extend from the first vertebra to the second vertebra. 16.The method of claim 15, wherein each of first attachment fixture and thesecond attachment fixture includes a first tapered region taperingtoward the first anterior cavity and a second tapered region taperingtoward the second anterior cavity to allow the steeper insertion angle.17. The method of claim 15, wherein the first movable insert and thesecond movable insert are cylindrical inserts.
 18. The method of claim15, wherein the first movable insert and the second movable insert arecylindrical that are smaller in length than the first and secondanterior cavity to allow lateral motion in addition to rotationalmovement.
 19. The method of claim 15, wherein the vertebral prosthesisfurther includes an aperture in the posterior region.
 20. The method ofclaim 19, wherein the vertebral prosthesis further includes one or morecomponents to promote bone growth.